<!DOCTYPE html>
<html>
  <head>
    <title>hello world</title>
    <meta charset="UTF-8">
    <!-- 为搜索引擎定义关键词: -->
    <meta name="keywords" content="HTML, CSS, XML, XHTML, JavaScript" />
    <!-- 为网页定义描述内容: -->
    <meta name="description" content="NIIT HTML5 教程" />
    <!-- 定义网页作者: -->
    <meta name="author" content="Jeff" />
    <!-- 每3秒钟刷新当前页面 -->
    <!-- <meta http-equiv="refresh" content="3" /> -->
    <!-- <base href="https://www.huel.edu.cn/" /> -->

    <link
      rel="stylesheet"
      type="text/css"
      hreflang="en"
      href="./css/myStyle.css"
    />
    <style>
      html {
        background-color: gray;
      }
    </style>
  </head>
  <body>
    <video src="https://www.runoob.com/try/demo_source/movie.mp4">
      Your browser does not support this video format.
    </video>
  </body>
</html>
